This week, the Sigma 135mm 1.8 ART lens shipped out to the people who pre-ordered it. Knowing the stellar reputation of the rest of the Sigma ART line, I did something I've never done before.. I pre-ordered it. I bought it with the intent to replace my Canon 135L which I love and use almost exclusively for my portrait work. I also use a Sigma 85mm 1.4 non-art, and the Sigma 50mm 2.0 Macro.

So when it arrived, I was excited to take it out for a spin side-by-side the Canon to see what, if any, differences I could see. All of these images are screen shots from Lightroom so you can see the full information. I am not affiliated with Sigma or Canon in any way, nor do I get paid for my views. I did not include any information on lens construction or shots in a general way. I wanted to focus only on how well it works for portraits when shooting on wide open apertures and how it compared to my current workhorse lens that I already know is brilliant.

The first image I took, gosh look at that bokeh!

Side by side, my first shock was that the COLOR is practically identical.

The Canon 135L lens is sharp and the color is buttery in it's transitions.

The Sigma 135mm 1.8 is somewhat sharper but in my opinion not as smooth in the color transitions on the petals from pink to purple. This could play a part in how much I like it for portraits.

The Canon 135L lens demonstrating why I love it so much.

The Sigma 135mm 1.8 at 2.0, to see how it compares to the 135L .. pretty hard to tell a difference.

And again the Sigma, this time at 1.8. The bokeh is wonderfully smooth.

While I was shooting the leaves, this titmouse landed on the feeder next to me. The Sigma whipped into focus quicker than a blink.

The titmouse then landed on a branch of that same tree.

100% crop of that previous image. Not brilliantly sharp but that's due to my own shaky hands. :)

So, cautiously impressed but not seeing a HUGE difference, I took it out with a test model since I'll be using it for portrait work.

First setup, I can see that the color still remains wonderful in both, but that added bit of wider aperture makes the spots of flowers in the background just a bit less distracting.

100% crop, the Sigma is a bit sharper.

Side by side in this one, I can see that the Sigma is a tiny bit more forgiving in the highlights and blown areas of her wings. The 1.8 bokeh in the background is quite lovely.

100% crop again

What strikes me again here is how very close the two lenses really are.

100% crop for the previous image again.

Pros and cons of both lenses: Overall, I found the Sigma to be more of what I wanted, and I'll sell the Canon. There's not a giant difference, but that's what I'd expect, given how great Canon's reputation for amazing glass is. The Canon 135L weighs less than the Sigma 135mm 1.8 ART. This could be an advantage or disadvantage to you, depending on how you shoot or carry in your bag. I'd also consider the Sigma a bit touchier in focus than the Canon, which could be an issue if you wiggle a lot like I do. You can see that in the last image above, I actually missed focus on her eyes and got her hair instead. I found that the Sigma was more forgiving in blown highlights than the Canon is, which is a big big deal to me because I tend to shoot backlit very very often. I also found the Sigma to be slightly sharper than the Canon. Sigma offers a USB dock that allows you to further customize how sharp it is (I just just called Fred at Sigma headquarters to confirm that this lens is dock-compatible). Lastly, I did feel like the Sigma focuses more quickly. When shooting kids that move, this is a huge point in it's favor as well. The 1.8 vs 2.0 aperture will give me an extra advantage in low light, which I also tend to do at the end of a session.